


Five and a Half

by bansheee



Category: Teen Wolf (TV)
Genre: AU, Alternate Universe - Siblings, Alternate Universe - Werewolves Are Known, Big Brother Derek, Boys Kissing, Fluff, M/M, Pining Derek, Step-siblings, Underage Stiles Stilinski, little brother scott
Language: English
Status: Completed
Published: 2014-09-22
Updated: 2014-09-22
Packaged: 2018-02-18 10:03:01
Rating: Teen And Up Audiences
Warnings: Underage
Chapters: 1
Words: 2,983
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2344385
Author URL: https://archiveofourown.org/users/bansheee/pseuds/bansheee
Summary: <blockquote class="userstuff">
              <p>God dammit, Derek knew. Derek knew that his little brother’s obnoxious, stupidly attractive best friend was seventeen.</p>
            </blockquote>





	Five and a Half

“I don’t know how it happened, mom.”  
  
Derek Hale-McCall knew this was the wrong thing to say as he watched Melissa, his step-mom, look over to Talia, his biological mom, with a raised eyebrow. He cringed when his mom and step-mom seemed to have a silent conversation with their eyebrows. If Stiles wasn’t sitting with his mouth shut in an uncharacteristic silence, he’d probably make a comment about it being hereditary.    
  
“Derek, explain what do you mean, ‘you don’t know how it happened’?” Talia asked.   
  
Derek cringed at the way his own words repeated to him back sounded.   
  
“He just… I don’t know, mom! One minute we were practicing in the field. Scott really wanted to be captain this year and I was helping him! Everything was fine, and Stiles needed better padding. And the next minute we—” Derek trailed off his sentence with another cringe, knowing that he was over explaining it to a point that his moms wouldn’t want to hear.   
  
“Were making out in the shed and leaving Scott alone to fend off a sick omega?” His step-mother’s voice had never sounded so disappointed. Derek felt terrible. He avoided looking at any of the people sitting around his kitchen table, especially Scott, who was still fighting back tears even though the gashes in his arm had long since healed.   
  
The room sat in a taught silence, the only thing interrupting it was small sniffles coming from his little brother. Even though his arm had healed, and Scott was too old to be crying, anyway, Derek could still hear the small sniffles. Derek had apologized countless times, but he still felt like an ass, though he’d never admit it.    
  
“Even if your brother can heal, you can’t just leave him alone,” his mom said. He looked up and saw her eyes glowing red, finalizing her part of the discussion.

Of course, Melissa still had hers. “Stiles is seventeen, Derek,” she (uselessly) pointed out. Out of the corner of his eye he saw Stiles uncross his arms to protest, but Melissa held up a finger to keep him quiet.   
  
God dammit, Derek knew. Derek knew that his little brother’s obnoxious, stupidly attractive best friend was seventeen.   
  
“I know,” he said in a very small voice. “He was just… convincing.”  
  
“Gross, Derek.” Scott said, his sniffles magically gone as he talked. Derek growled at him. He was totally playing up the ‘pain’ in his arm to get Derek in more trouble. When Scott changed his eyes to challenge Derek, the older boy let his claws grow out.  
  
Talia let out a quiet warning growl, ceasing the claws and fangs at the table before they came out. Melissa stared at him for a few seconds, processing, before she rubbed the bridge her nose.   
  
When she said nothing, Derek tried to explain some more. “He just… It was his fault!” he shouted, pointing to Stiles, who didn’t bother and protest. “We were practicing, and it was hot out, and—”  
  
Okay, stop!” Melissa interrupted, holding her hand up so Derek wouldn’t accidently say something that he’d immediately regret.   
  
“Even if this is our territory,” Talia stated, covering up Melissa’s hand gently and taking over, “there are still things in the preserve that we have to be on alert for. You can’t just leave your little brother alone outside.”    
  
“Mom!” Scott whined, fake tears forgotten. “Don’t say it like that! That makes me sound like a baby!”   
  
Derek immediately pounced. “You are a baby! If you wouldn’t have thrown that ball in the woods and ran after it—”  
  
“Derek!” Talia flashed her eyes at her oldest son again. “I don’t think you’re in any place to be lecturing your brother about maturity right now.”  
  
Derek sat back in his seat with a huff, crossing his arms in a pout. He finally looked over towards where Stiles was sitting next to Scott, staring straight at Derek. Derek could feel his ears go warm as Stiles unabashedly grinned at him. Stupid Stiles. Stupid, attractive Stiles, still living in the bliss of the few moments of not being punished because his dad hadn’t arrived yet.  Derek ignored the way his heart thrummed as Stiles refused to look away.   
  
Until, of course, there was a knock at the Hale-McCall’s front door.   
  
Derek fully enjoyed the way the smile dropped off of Stiles’ face when Talia called, “come in, Sheriff,” and the door handle turned. He watched as Stiles sank further into his chair when his dad locked eyes with him, not removing them while he too found a place at the kitchen table.   
  
The Sheriff accepted a cup of coffee, “with two sugars, thanks Talia,” he said, still not looking away from his son. Stiles opened his mouth, probably to protest the sugar, but the look on the Sheriff’s face had him shutting his mouth. “Okay. Without _details_ ,” he said to his son, ignoring the scoff that escaped, “tell me what happened.”   
  
*  
  
Derek looked to the ground. Derek stared at the ground because he was not looking at Stiles Stilinski. He studied the grass blades because _seventeen year old, dammit_ , Stiles had tugged his Incredible Hulk t-shirt off and threw on the ground near their stuff in favor of a t-shirt that he could get dirty. Derek watched the way his old lacrosse shoes crunched along the grass blades because Stiles had somehow grown muscles in his arms and a thick line of hair on his lower stomach, and Derek had not been ready for that.   
  
Because Stiles was seventeen! He had just finished his junior year of high school!   
  
He got padding on quietly, listening to the way Stiles and Scott blabbered on about the team this year and how Stiles just ‘had to practice more’ if he didn’t want to sit on the bench all year, and how much this would impress Allison. Looking down, Derek’s eyes widened when he saw the muscles in Stiles’ calves. Derek was sure he’d make first line based solely on those. He pried his glance away from the dark hairs that had seemingly grown since the last time that Derek had seen Stiles, on Christmas vacation.   
  
“Derek!” Scott yelled, snapping him out of his trance. “Are you going to help me make captain or not?” Scott asked impatiently from where he and Stiles were throwing a small white lacrosse ball back and forth. While he jogged over, he pretended not to be proud as Scott told Stiles that, “Derek was team captain _forever_ ago when he was a senior.”   
  
“Jesus, Scott, it wasn’t _forever_ ago. It was four years.” Derek pointed out. If a hint of defensiveness snuck its way through his tone, neither of the younger boys noticed.   
  
“Whatever,” Scott replied. “Derek, you and Stiles go in front of the goal net. We’ll do 2-to-1’s to warm up, and then practice some goal stuff.”   
  
Derek looked over to where Stiles was grinning. “You’ll make a great captain, buddy,” he said as he gave him a mocking salute. Scott rolled his eyes and shoved Stiles towards the goal net, laughing as he stumbled over his own shoes. Derek’s stomach turned with content butterflies at the way Stiles’ laughter filled the backyard. He followed behind the teen, still looking steadily towards the ground and not at the expanse of moles that crawled up his arm and got lost under his practice t-shirt.   
  
The two boys stood in close proximity as Scott stood a few yards away. Derek stood very still, knowing that if he moved at all his arm would brush up against Stiles’. He could smell excitement and nerves coming off the boy in large waves.   
  
Inhaling all the different scents Stiles was radiating, Scott managed to get through them with little problem.   
  
“Come on, Derek! You actually have to try. You promised!” Scott complained when he fished the ball out of the goal net.   
  
Derek glared at his brother, avoiding Stiles’ confused glance from the ground. In his stupor with the way Stiles smelled, Scott had managed to shove Stiles over and easily get past him to score. Derek held his hand out to Stiles to help him up.   
  
They went like this for a while, Scott starting up and practicing different techniques to avoid the Stiles and Derek duo. As they went on, Derek and Stiles got exponentially better at sensing and blocking Scott’s goal attempts, Derek managing to ignore the soft little grunts as he and Stiles collided with eachother repeatedly. Every time they managed to block him, Derek soaked in the grin, the high five, or the cheer that Stiles would give him.

These feelings for his little brother’s obnoxious best friend weren’t anything new. At first he’d been annoyed at the little things; the way he always tapped his fingers in a thrum of nervous energy, the way he’d laugh like it was surprised out of him, and the way every pen he held in between his made-for-porn fingers had to come to his mouth at one point or another. The obsessive annoyance got him thinking about the boy all the time, and after one too many times of Scott or Cora pounding on the bathroom door to yell at him for taking up all the hot water _again_ , Derek had finally come to terms with his feelings.   
  
Of course, _of course_ , Stiles was still seventeen, and his brother’s best friend.   
  
After one particular quick-step from Scott that used a little too much wolf power, Stiles and Derek both found themselves on the ground on their backs. Ignoring Scott running around the field at the edge of the preserve chanting his own name, Derek jumped back onto his feet and walked over to Stiles.   
  
“Are you okay?” he asked after a second of Stiles just staring at the sky.   
  
“Yeah, just feeling very human. Need a minute.” Stiles grunted out, coughing as the air filled his lungs back up.   
  
Derek knelt down next to him. He hesitated for a second, before putting his hand on Stiles’ stomach. He winced and watched as the veins in his arms filled with the black color that represented the pain he was pulling from Stiles.   
  
After a few seconds he removed his hand, and Stiles sat up. “Thanks, Derek. I probably just need some more padding.”   
  
Eyes not leaving the big brown circles of Stiles’, Derek said, “We have some other stuff in the shed that might fit you better.”   
  
“Will you help me find it?”   
  
Derek should say no. He should tell the boy to hurry up and grab them so Scott would shut up and keep practicing.   
  
“Sure.” He held out his arm to pull Stiles up off the ground again. “Hurry up though; we can’t just ditch Scott.” Derek added to make himself sound less hopeless.   
  
Stiles laughed. “He’s off in his own little captain-pants-Allison-lovey-dovey world right now. He’ll be fine for a few minutes.”  
  
Something in the back of Derek’s brain told him he shouldn’t follow Stiles towards their moms’ storage shed. But when he looked over to where Scott was throwing the ball up to himself over and over, he figured he was fine and ran off to help Stiles.   
  
When he arrived at the shed on the other side of the yard, Stiles was already inside. He smiled fondly as he looked around at all of the old Hale-McCall toys. There was a layer of dust on the RC cars that he and Scott would absolutely _shred_ eachother apart to control, as well as a kid-sized pink Barbie dream car that Cora would never admit she slept in one night when she refused to leave it. He felt his chest rumble with warmth as he looked at the various bats, balls, gloves, and other sports equipment that had made up the first years of his life.   
  
He finally scanned the room and found Stiles. The boy was digging through an old box filled with random lacrosse gear; he could hear the small sigh Stiles gave out when he tried on a glove, only to have it fall off when he waved his hand around. Derek knew Stiles was aware of his presence, but he still took the few seconds before Stiles turned around to admire the way the muscles in his shoulders shifted as he dug through the box.   
  
With a small cough to finally announce his presence, Derek waited for the boy in front of him to find what he was looking for. When Stiles stood up a few moments later empty handed, Derek raised an eyebrow at him as if asking, ‘well?’   
  
“Guess I should have brought my own stuff. Kind of just figured Scott would want to spend the first week of summer playing video games instead of already worrying about being lacrosse captain,” Stiles said with a small shrug, tone far from upset. Derek could hear the boy’s heartbeat pick up even more from the rapid way it had been beating. His own was stuttering in his chest as Stiles took a few steps closer. With a small lift of his stupid, perfect lips, he added, “We should probably go back out.”   
  
“Yeah,” Derek mumbled, thankful in that moment that Stiles was not a werewolf so he couldn’t hear how badly Derek did not want to. “Scott will be waiting. He’ll be pissed if I ditch him again.”   
  
“Might even come looking for us,” he added with zero concern in his tone. Stiles was right in front of him now; Derek could see the small beads of sweat around his hairline from the warm air in the tiny, tiny shed. Derek didn’t dare breathe in through his nose, as he knew the scent would be too much for him to handle. Without thinking, Derek brought his hand up right next to Stiles’ cheek, before quickly pulling it back.   
  
“Stiles—” he started with a small bit of hesitation.   
  
Stiles didn’t pull back, wasn’t hurt, as if he was expecting this to happen. “You act like I’m that much younger than you. It’s five years. In ten years that wouldn’t even matter.”  
   
Derek didn’t fret at the thought of ten years down the road and he didn’t know if that scared him or not. “Six,” was the only thing he could manage to say.   
  
The corner of Stiles’ mouth lifted just slightly enough that Derek would have missed it if he hadn’t been staring right at it. “Five and a half.”   
  
His breath caught in the back of his throat as Stiles closed the space between them and pressed their lips together. _Finally, finally,_ Derek’s brain shouted at him as he allowed himself to press a hand to Stiles’ waist, his top two fingers shifting the fabric of his t-shirt away and coming into contact with bare skin. Derek’s chest thudded as Stiles’ hands gripped his shoulders. The younger boy was only a few inches shorter, and would likely be taller than him by the time he was through his last growth spurt in his early twenties. He ignored the yelling from outside as he felt Stiles drag his fingers through the little hairs on the back of his neck, and sighed when Stiles pushed himself closer, backing Derek into a table.   
  
Derek finally allowed himself to breathe in through his nose, and when the sharp scent of Stiles’ arousal filled it, he finally allowed himself to wrap both of his hands around the boy’s hips, and tug him flush up against him. He let the sound of Stiles’ erratic heart and small moans in the back of his throat fill his ears and drown everything else out.   
  
Stiles pushed forward again, as if there was any room between them to begin with. Derek ignored the table digging in his back as he opened his mouth and deepened the kiss.  
  
While hating himself for doing so, Derek pulled back when he felt Stiles’ hands slide down and reach under his shirt. Derek wanted so badly to allow the boy anything. Stiles rolled his eyes in silent protest, and Derek gave him a small smile. “Did you hear something?”   
  
Stiles chuckled. “I don’t care,” was all he said, before pulling Derek’s mouth back to his.   
  
*  
  
“So, let me get this straight,” the Sheriff started, glaring at his son for the snort that came out at his word choice. Stiles still cringed at the look his dad was giving him. “You called me at the station on my emergency line to come ‘hang out with Scott’, only to ditch him, to seduce Derek in the shed, and when Derek _heard_ Scott cry out from _getting attacked by an omega_ , you did nothing?”   
  
Derek was already frowning and feeling small from his mothers’ disappointment, and adding Stiles’ dad’s disappointment was just the icing on the cake.   
  
When both of the boys felt and looked sufficiently remorseful enough, Sheriff Stilinski spoke again. “I guess it wasn’t all bad. It gave me a reason to ground you until you’re conveniently _eighteen_.” Stiles instantly opened his mouth to protest, but one look from his father had him closing his mouth. “Unless what’s about to come out of your mouth is a sincere apology for making me drive here in the middle of my shift to arrest an omega that you didn’t help Scott with, I don’t want to hear it. Derek is still welcome to visit, but the bedroom doors are open for another year. In fact, make sure to invite him to dinner soon.” Derek didn’t miss the way the Sheriff’s tone suggested he’d be conveniently cleaning his gun or taser at this dinner.   
  
Derek watched as Stiles looked to his father, probably wanting to protest again. However, when the boy turned back to Derek, the small smile that lifted up the side of his mouth was enough to make the wait not seem as bad.  
  
“Nine months, Dad.” 

**Author's Note:**

> I put Stiles at seventeen here, but he’d be eighteen at the end of his junior year with the way canon works, I think? Idk. If Jeff can ignore canon facts then I can too. I wrote a Harry Potter fanfiction really close to this. If you recognize it, congrats you found me. 
> 
> Visit me on tumblr for more Sterek fun: bansheehale.tumblr.com


End file.
